This thesis is devoted to developing autonomous underwater vehicle(AUV) navigation system and especially navigation filter with sensor failure detection and recovery. AHRS(Attitude & Heading Reference System) and flow meter are used as self-contained and dead reckoning navigation sensors. SSBL(Super Short Base line) system is acoustic position detection sensor and used as external sensor for AUV navigation system.
Sensor failure is faital in case that the sensor is used as external measurement of Kalman filter therefore detection and recovery of sensor failure is one of the core of navigation filter. In this thesis, Fuzzy theory is proposed to detect external sensor failure and provide valid external measurement to Kalman filter avoing filter divergency and instability. 2 dimensional simulation result shows that acceptable failure detection and recovery for various trajectories.